1、Nonlinear OpticsTextbooks: (1)錢士雄，王恭明錢士雄，王恭明非線性光學非線性光學-原理與進展原理與進展復旦大學復旦大學 (2)石順祥石順祥非線性光學非線性光學西安電子科技大學出版社西安電子科技大學出版社 (3)葉佩弦葉佩弦非線性光學物理非線性光學物理北京大學出版社北京大學出版社 (4)李淳飛李淳飛非線性光學非線性光學電子工業出版社電子工業出版社 (5) Robert W. Boyd, Nonlinear Optics， 3rd Edition (6) Y. R. Shen, Nonlinear opticsIntroduction1.What is nonlinea

2、r Optics and the development history of nonlinear optics2. Material Response to the Light 3. Classification of nonlinear optical effects4. Wide applications ( Optics (from 16th century to 1960) a) The nature of optics(the properties of waves and particles) (electromagnetic field theory and quantized

3、 theory on light) b) Interaction between light and matter (only linear interaction before the laser was invented)1.What is nonlinear Optics?Linear OpticsThe output is proportional to the input field and no interactions and energy transfer between waves with different frequencies, which originate fro

4、m the linear polarization of the medium.P = e e0 c cEThe absorption and refraction index keep constant with the intensity and frequency of the input light.Light travels indepently in the linear materialsNonlinear OpticsP = e e0 c c(1)E + e e0 c c(2)EE + e e0 c c(3)EEE + For the input field with very

5、 high intensity that are comparable with the intensity of average Coulomb field of the light atom, the polarization of the medium must be written as:This nonlinear polarization can result in lots of nonlinear optical effects which will be learned in this course.The very early nonlinear optics(before

6、 the birth of laser)Pockels effect :1893 by F. C. Pockels (Germany) Linear dependence of the refractive index on the intensity of the electric field Electrooptical effectEnanisotropyisotropyglass,Elliptically polarized beamKerr effect: 1875 by John Kerr Electrooptical Kerr effect Electrically induce

7、d birefringence that is proportional to the square of the electric field Linearly polarized beamElliptically polarized beamglass2anisotropyisotropyglass,En VJohn Kerr FRS (1824 1907) , Scottish physicistAn effect in which a very strong linearly polarized light field produces anisotropy in the refrac

8、tive index of an isotropic medium, usually a liquid. Optical Kerr effect:Linearly polarized beamKerr cellPumping beamby C. V. Raman in 1928. Raman Effect:the scattering of light by matter, accompanied by a noticeable change in the frequency of the scattered light. Nobel Prize in 1930Brillouin scatte

9、ring named after Lon Brillouin, occurs when light in a medium (such as air, water or a crystal) interacts with time-dependent optical density variations and changes its energy (frequency) and path. by Lon Nicolas Brillouin in 1922.C. V. Raman(1888-1970) Indian physicistLon Nicolas Brillouin(1889-196

10、9)Franch physicistThe nonlinear optics developed slowly for the lack of experimental conditions before the birth of laser! Stimulated emission, The MASER and The LASER (1917) The concept of stimulated emission Albert Einstein (1928) Observation of negative absorption or stimulated emission near to r

11、esonant wavelengths, Rudolf Walther LadenburgH. Kopfermann and R. Ladenburg, Experimental Proof of Negative Dispersion, Nature Volume 122, 438-439 (22 September 1928) hE1E2AbsorptionE1E2hSpontaneous Emission E1E2hhhStimulated EmissionLASER(MASER)Light (Microwave) Amplification by Stimulated Emission

12、 of Radiation The Maser （Microwave Amplification by Stimulation Emission of Radiation）Two groups were working on Maser in 1950sAlexander M. Prokhorov and Nikolai G. Basov (Lebedev institute of Moscow)Charles H. Townes, James P. Gordon and Herbert J. Zeiger (Colombia University) Shared the Nobel Phys

13、ics Prize in 1964 The LASER (1951) V. A. Fabrikant “A method for the application of electromagnetic radiation (ultraviolet, visible, infrared, and radio waves)” patented in Soviet Union. (1958) Townes and Arthur L. Schawlow, “Infrared and Optical Masers,” Physical Review (1958) Gordon Gould definiti

14、on of “Laser” as “Light Amplification by Stimulated Emission of Radiation” (1960) Schawlow and Townes U. S. Patent No. 2,929,922 *(1960) Theodore Maiman Invention of the first Ruby Laser (1961) Ali Javan The first He-Ne Laser Theodore Maiman1927-2007American engineer and physicist Properties of Lase

15、r BeamA laser beam is intense is coherent has a very low divergence can be compressed in time up to few femto seconds Applications of Laser Medicine, Research, Industry, Military, Communication, Art, Information technology, Entertainment, *Strong coherent light source for nonlinear optical effectsTh

16、e development of nonlinear opticsI: 19611965 new phenomenon of NLO SHG, DF,SF,OPA, SFII: 19651969 nonlinear optical spectrum, transient nonlinear optics, and new NLO devices were designedIII: 1970now widely and fully developed NLO medium: from solid medium to gas/atom evaporation/liquid and even to

17、solid crystals NLO orders: from 2nd order to 3rd, 5th or even high order harmonic effectsNLO types: from common non-resonant NLO to resonant NLOTime domain: from ms, ns to ps, fs, and even to as Ruby laserQuartzPrism694.3nm347.2nm694.3nmSHGP. A. Franken, A. E. Hill, C. W. Peters, and G. Weinreich,Ge

18、neration of Optical Harmonics, Phys. Rev. Lett. 7, 118, 19611961 Kaiser and Garrett: Two-photon absorption (TPA)1962 Optical Sum Frequency (SF)31212312zTRQ-switchingKerr cellRuby laserPRnitrobenzeneStimulated Raman Scattering (SRS)Stokes line1965 Optical Parametric Amplification Optical Parametric O

19、scalitionStimulated Brillium Scattering (SBS)In the early and middle of 1960s, Bloembergen and his students built up the basic theory of nonlinear optics based on the medium polarization and coupled waves.Nicolaas Bloembergen Nobel Prize in Physics (1981) Under high input intensity, Self-Focusing fo

20、rms 1964年預言并觀察到光子回波 1967年發現了光學自感應透明 1969年預言并觀測到光學章動 1972年觀察到光學自由感應衰減研究物質在共振條件共振條件下受到強相干光場強相干光場作用時，在小于物質內部縱向及橫向弛豫時間的時域范圍內所發生的光學現象。諸如光子回波、光學自由感應衰減、光學章動、自感應透明等等。 瞬態相干效應瞬態相干效應瞬態相干光學效應瞬態相干光學效應目前主要應用在固體和氣體介質中共振譜線增寬性質的研究和激發態弛豫參量的測量。 70年代初開始非線性光學的應用研究：一方面給非線性光學注入了持續發展的動力；另一方面研究成果進一步豐富了非線性光學的內容。擴展相干光源擴展相干光源

21、倍頻、和頻、多倍頻： 藍光、紫光、紫外光 差頻：紅外激光 參量振蕩：可見光、近紅外、紅外、遠紅外 可調諧激光器 受激Raman散射、四波混頻、參量振蕩（氣體）：紫外光、真空紫外光可調諧激光器 相位共軛技術相位共軛技術 四波混頻、受激布里淵散射四波混頻、受激布里淵散射 消除光束傳播過程中的相位畸變，提高成像質量 消除激光器內元件的畸變及熱效應，改善激光輸出質量光計算、光通信及光電子技術光計算、光通信及光電子技術 光學邏輯器件 （與、或、非、與非） 光調制器（半導體中的非線性等） 光存儲器（光子回波時域相干光子存儲） 光纖通信、光孤子、光學壓縮態光譜與物質研究中的非線性光學方法光譜與物質研究中的非

22、線性光學方法（開創者：Bloembergen、肖洛-激光光譜，1981年諾貝爾物理學獎） 飽和吸收光譜 雙光子吸收光譜 相干瞬態光譜 四波混頻光譜 表面與表面吸收的檢測非線性光學晶體材料非線性光學晶體材料: 我國處于國際領先地位，其中偏硼酸鋇（BBO ）和三硼酸鋰（LBO）、氟代硼鈹酸鉀 （KBBF）三種晶體為我國發現并批量生長，他們性能優良，開創了激光紫外倍頻的新紀元。 世界上第一個“中國牌”的非線性晶體新材料晶體BBO于1984年問世，這是中國科學院福建物質結構研究所首創的非線性光學晶體材料。 倍頻效率高，抗光損傷能力最高，調諧寬度最寬的優質紫外倍頻晶體。激光器里最常用的三種類型非線性光學

23、晶體是BBO、LBO和KTP。前兩者是中國發明，后者為美國杜邦公司發明，但足夠大尺寸的KTP也是在中國生長出的。KBBF晶體是目前中國獨有的技術，是吸收邊最短的深紫外晶體（200nm）。 1990年以來，非線性光學在如下領域取得了重大進展：年以來，非線性光學在如下領域取得了重大進展： 飛秒非線性光學性質的研究，以及飛秒化學和飛秒生物學 有源、無源半導體器件在光通信中的應用 大容量、高速光存儲 X激光器 壓縮態的實驗進展 非線性光學技術已經成為高科技，尤其是光電子技術、光子學、光子技術、納米材料等學科的基礎。 非線性光學現在已經是光學一個非常重要的學科分支，內容涵蓋了各種非線性光學效應以及激光和

24、物質相互作用及其應用等領域。 隨著科學研究的不斷深入，目前的主要任務仍然是在揭示新的非線性光學現象、探索其產生機制、特點以及應用。Introduction1.What is nonlinear Optics and the development history2. Material Response to the Light 3. Classification of nonlinear optical effects4. Wide applications ( DBJDHBE0ttEJHBPEDmme00022002trEEeemMaxwell Eqs. and Material Eqs.

25、2. Material Response to the Light Linear optics wave equation:If the nonlinear effect can not be ignored, the wave equation is rewritten as follows,22200022NLrPttm e emEEwhere, P=PL+PNL.So the nonlinear polarization PNL is the origin of the new optical field .Material Response to the Light (scalar a

26、ssumption)P = e e0 c c( (1)E + e e0 c c( (2)EE + e e0 c c( (3)EEE + P: induced polarization of mediume e0: dielectric constant of vacuumE: electric fieldc c( (1) : first-order susceptibilityD = e e0E + P = e eE In linear optics: n2 = 1 +c c( (1)Wuhan UniversityIn generalaE1)2()3()1()2(ccccwhere is t

27、he intensity of average Coulomb field of the lighter atom, its value is aboutaEcmV /108Nonlinear Terms Second-order term, c c( (2)EE and typical second order nonlinear optical effects1.Supposing input field is monochromatic, E=(1/2)E()e-it+c.c. c(2)E2 static voltage appears across the sample c(2)E2

28、cos(2t) second harmonic generation(SHG) 2.Two input frequencies 1 1,2 2 E=E1(1)e-i1t+E2(2)e-i2t +c.c. c(2) E1(1) E2(2)cos(1 2)t sum frequency (SF) c(2) E1(1) E2*(2)cos(1 2)t difference frequency (DF)P = e e0 c c( (1)E + e e0 c c( (2)EE + e e0 c c( (3)EEE + 3. Optical parametric oscillation (OPO) Opt

29、ical parametric amplification (OPA)Input two waves with s and p (s p) i p- s idle frequency s p i the signal light can be amplified OPA OPO = OPA + ResonatorFor powerful pump lightDF processThird-order term, c c(3)EEE and typical effectsc(3)(3) E() E()3 3 cos(3(3t) ) 3rd harmonic gernerationFour wav

30、e mixing 1( )( )2 ( ) ( )3 n = n0+n2I stimulated Raman scattering (SRS)self-focusing and self phase modulationoptical Kerr effect (OKE)saturation absorption (SA)two (twin)- photon absorption (TPA)Introduction1.What is nonlinear Optics and the development history of nonlinear optics2. Material Respon

31、se to the Light 3. Classification of nonlinear optical effects4. Wide applications ( 3. Classification of nonlinear optical effectsNonlinear optical effects can be divided into two classes:(1) parametric interaction effects The energies are transferred only between the waves, e.g., SHG, THG, OPA, OP

32、O, FWM, DFWM, (2) non-parametric interaction effects The energies are transferred between waves and also between the wave and matter. e.g., SA, TPA, SRS, SBS, Introduction1.What is nonlinear Optics?2. Material Response to the Light 3. Classification of nonlinear optical effects4. Wide applications (

33、 Sending infrared light into a crystal yielded this display of green light: Nonlinear optics allows us to change the color of a light beam, to change its shape in space and time, to switch telecommunication systems, and to create the shortest events ever made by Man.Nonlinear Optics produces many ex

34、otic effects and has wide applications.wide applications (VISIBLEUVIRFIRVUVMW-raysX-rays(1) Nonlinear optical effects new methods to have new coherent lightwide applications ()()()()()(2121)()(nnncEEEP1n 2(2) surface physics and surface SHG)()(/)(222sNLsssPce2c4E(2) surface physics and surface SHG (continued)a) to detect the molecular orienta